After three weeks in Georgia reporting on the war and its aftermath, I find one conversation sticks with me. I had arrived in Karaleti, a Georgian village north of Gori. I had gone there with a group of foreign journalists in a Russian army truck; our ultimate destination was Tskhinvali, in South Ossetia. Several houses along the main road had been burned down; an abandoned Lada lay in a ditch; someone had looted the local school.

Refugees from Karaleti and nearby villages gave the same account: South Ossetian militias had swept in on August 12, killing, burning, stealing and kidnapping. Sasha, our Kremlin minder, however, had a different explanation. "Georgian special commandos burned the houses," he told us. I demurred, pointing out that it was unlikely Georgian special commandos would have burned down Georgian villages north of Tskhinvali, deep inside rebel-held South Ossetia. Sasha's face grew dark; he wasn't used to contradiction. "Those houses suffered from a gas or electricity leak," he answered majestically.

Despite Sasha's inventive attempts to lie, it's evident what is currently happening in Georgia: South Ossetian militias, facilitated by the Russian army, are carrying out the worst ethnic cleansing since the war in former Yugoslavia. Despite the random nature of these attacks, the overall aim is clear: to create a mono-ethnic greater South Ossetia in which Georgians no longer exist.

Before Georgia's attack on Tskhinvali on August 7/8, South Ossetia was a small but heterogeneous region, a patchwork of picturesque Georgian and Ossetian villages. Georgia's government controlled a third; the separatists and their handlers from Russia's spy agencies controlled another third, principally around the town of Tskhinvali; the other third was under nobody's control. Surprisingly, both groups coexisted in South Ossetia.

A week after the conflict started I drove up to Akhalgori, a mountain town, 41km north-west of Tbilisi. South Ossetian militias, together with Russian soldiers from Dagestan, had captured the town the previous evening. Most residents had already fled; by the bus stop I found a group of women waiting for a lift. The town had no history of ethnic conflict, they said. Its population was mixed. Now almost all the Georgians had fled. I asked a militia leader, Captain Elrus, whether his men had ethnically cleansed Georgian villages between Tskhinvali and Gori. "We did carry out cleaning operations, yes," he admitted.

The Kremlin's South Ossetian allies have re-established the old Soviet borders of South Ossetia. This new, greater territory will, as South Ossetia's parliamentary speaker made clear on Friday, become part of the Russian Federation: a large Georgian-free enclave stretching almost to the suburbs of Tbilisi.

Back in Karaleti, meanwhile, villagers are continuing to flee. After August 12, dozens escaped on foot, walking for three days across the fields, hiding from the militias and eating wild plums. South Ossetian gunmen are preventing refugees from returning, and forcing the few elderly residents who remain to leave as well. The Russian military has done nothing to stop this. Its peacekeeping mandate is little more than a pretext for occupation. There are Russian checkpoints between Gori and Tskhinvali.

EU leaders meet today in Brussels to discuss how to respond to Russia's invasion and occupation of Georgia, and President Dmitry Medvedev's unilateral recognition of South Ossetian and Abkhazian independence. Already the European appetite for sanctions appears to be fading, with the French and the Germans signalling an unwillingness to punish Moscow. But the EU needs to be clear about what is happening. Russia is not merely redrawing the map of Europe but changing its human geography too.